Help with my 84 hot air GN

[Jerryl]

when it cuts out it stumble's and has irattic idle and just dies, its not like shutting the key off, When I did the iac reset I took the throttle body off and cleaned the IAC very good, couldnt get the rpms that low only like 800-900rpms, when i was done setting the perimeters in the tps it surged up and down for a minute then stayed at a constant idle. Ran great with the rpms at 800-900 rpms, until i got home then stumbled and died. I will check to see if the grounds under the ac comp are clean and tight. Also I tested my old module , it failed, And got a module off of Esasky from this forum and just put it on after I got it assuming that one worked, took it off today got it tested and that also failed. I have a 86-87 that passed so I will order a caspers adapter and plate to compete the conversion to see if that helps, For the conversion is the 86-87 module, coil, ecm, caspers adapter and plate all that is needed or do I have to upgrade the MAF to the LT1 with a translator aswell??? thanks man much appreciated

How were the modules tested?
You need to verify if the car looses spark when it stalls . . . . . . it sounds like you have a vacuum leak as well.
With a scantool you would be able to see the idle BLM change and probably max out.

Leave the MAF for now and replace one thing at a time.
You would need scantool to determine the condition of the MAF.

 

[mccallumfam1]

How were the modules tested?
You need to verify if the car looses spark when it stalls . . . . . . it sounds like you have a vacuum leak as well.
With a scantool you would be able to see the idle BLM change and probably max out.

Leave the MAF for now and replace one thing at a time.
You would need scantool to determine the condition of the MAF.

I got the modules tested on a 10000$ machine and the two 84-85 modules failed, I also got a 86-87 module that I got tested and it passed so my next move is to order a caspers conversion harness and and adapter plate like you said in the earlier reply, Is that all that is needed for a Ignition conversion? I already have an 86 ECM in the car. Im almost certain I have an ignition issue here jerryl. Grounds under the ac comp seem to be good aswell, what is the best advice u can give me on how to check for vacuum leaks? smoke test? cigar test? I know that a Scan tool would make it alot to diagnose but I dont have one yet but its a definate must in the soon future for me. Like the old saying goes "doing more with less"Appreciate the help man. [/quote]

 

[mccallumfam1]

If it where a crank sensor issue, I would have no start, If it where a cam sensor issue, I would have a miss, I am strongly leaning to a module or vacuum problem, maybe even both.... The car idled super fine today and the rpms where steady at 800-900 rpms, Is this a good idle?? why would it run if the module tested bad?

 

[standupjskiguy]

Just some thoughts.

I would find out what code your SES light is trying to tell you.
here is a link how
http://www.extreme-check-engine-light-codes.com/GM OBD1 Decoder.htm
you count the blinks of the light, it will flash each code three times before moving on the the next code.
write it down in case you have many.

I thought I had read on this site that you cannot use an 84-85 MAF with the 86-87 ecm.
This is one of the reasons I leave my 85 alone.

That screw that you refer as idle adjustment is not an idle adjustment like the old days.
It sets the range for the IAC pulses. I don't know what happens if you get it out of whack.

Open loop mode definition from the internet:
A non-feedback mode of operation which a feedback system resorts to when the engine is started while it is still cold. During this period, the oxygen sensor isn't yet able to supply reliable data to the computer for controlling the air/fuel mix ratio because the engine isn't yet warmed up. So mix control is handled by a program stored in computer memory

Closed loop means it is now adjusting the engine based off sensors.
It sounds kinda like your car has a problem running closed loop but you say this problem happens when the engine gets really hot
like after a half hour. I think the engine goes into closed loop after about 15 minutes. So maybe if the car is overheating, it could be some
kind of vapor lock. Have you got anyway to check how hot your engine is really getting?

If you take off the intake pipe to you air filter when the engine is hot. Then start the car, when it tries to die, spray a small amount
of starting fluid into the intake. If the engine runs better, you are too lean. If it makes no difference it maybe ignition related.

I don't know what wires are on there but I know there are some crappy ones out there. If yours are radio suppression carbon
track type, you need to check each with an ohm meter. They should read 10-20,000 ohms each. If you get one that reads way high,
you may have an internal arcing that burned the inside. I have had this issue with new after market wires on a non turbo car.
And it caused the car to stall while idling coming to a stop. Look inside the boot, do you see a bright shiny wire in the center bent
around to the metal clip the contacts the plug or is it dark grey looking? If it grey, then it is radio suppression.

Good luck

 

[Jerryl]

I got the modules tested on a 10000$ machine and the two 84-85 modules failed, I also got a 86-87 module that I got tested and it passed so my next move is to order a caspers conversion harness and and adapter plate like you said in the earlier reply, Is that all that is needed for a Ignition conversion? I already have an 86 ECM in the car. Im almost certain I have an ignition issue here jerryl. Grounds under the ac comp seem to be good aswell, what is the best advice u can give me on how to check for vacuum leaks? smoke test? cigar test? I know that a Scan tool would make it alot to diagnose but I dont have one yet but its a definate must in the soon future for me. Like the old saying goes "doing more with less"Appreciate the help man.

[/quote]

Well . . . .The 84/85 module is different and will not even work with a Caspers tester, unless you have the correct pigtail, that was the reason I asked “How”.
To the best of my knowledge, the 84-85 mudules pretty much stand on their own.
So, it doesn't matter if the shop/store has $1,000,000 piece of equipment just to test modules. It will indicate a “fail” every time, unless they have this information.

Re: Conversion.
Yes, that is all you need.

If I remember (CRS here . . LOL) the SES code was “12”, so that is good.
Now . . . If you drive the car, get an SES code, and then when you inspect it is code 12, the ECM is losing power and resetting.
If the grounds are correct, you will need to check other connections. (Battery, body grounds, starter connections, ECM connector at the battery, etc)

Also . . . Hard starting . . . can very possibly be the module, a bad wire, FP relay, etc.
I have chased a major intermittent problem for 9 years and finally found it. It showed up under the right circumstances and could not be seen on a scantool.
It is so stupid small I am not even going to post about it. I learned a heck of a lot in the process, BUT also gained a lot of grey hairs in the process! LOL

If it where a crank sensor issue, I would have no start, If it where a cam sensor issue, I would have a miss, I am strongly leaning to a module or vacuum problem, maybe even both.... The car idled super fine today and the rpms where steady at 800-900 rpms, Is this a good idle?? why would it run if the module tested bad?

I have seen crank sensors act up as well, and that is why I say “Check for spark when she quits and will not restart”
Having stated all that . . . . the messages and my responses are more than likely very conflicting to you in many ways.

If it does not shut off like turning the ignition off, it is probably not the crank sensor.
If it does not start due to “heat soak”, a 10 minute cool down will not be significant for the module to “start and run fine”.

Stock idle is around 775-800 so it looks a lot closer than before.
Make sure the throttle is not sticking or transmission cable too tight.
You can disconnect the transmission cable at the T.B. (DO NOT DRIVE IT THIS WAY!) and see of the idle drops.

Best way to check for vacuum leaks . . . no such thing . . as some people check differently based on application and tools.
Smoke test is good one, but requires a pressure set-up and smoke machine.
Carb cleaner sprayed around the other areas is good, for bigger leaks.
Propane bottle works too, but on a HA it is almost impossible if you have the mechanical fan.
My method . . . Pinching the hoses one at a time and listening/monitoring RPM is the better method . . . once you find the hose, you can spray with some carb cleaner. . . . Oh, I verify the O2's on the scantool when I spray . . . LOL

 

[mccallumfam1]

Just some thoughts.

I would find out what code your SES light is trying to tell you.
here is a link how
http://www.extreme-check-engine-light-codes.com/GM OBD1 Decoder.htm
you count the blinks of the light, it will flash each code three times before moving on the the next code.
write it down in case you have many.

I thought I had read on this site that you cannot use an 84-85 MAF with the 86-87 ecm.
This is one of the reasons I leave my 85 alone.

That screw that you refer as idle adjustment is not an idle adjustment like the old days.
It sets the range for the IAC pulses. I don't know what happens if you get it out of whack.

Open loop mode definition from the internet:
A non-feedback mode of operation which a feedback system resorts to when the engine is started while it is still cold. During this period, the oxygen sensor isn't yet able to supply reliable data to the computer for controlling the air/fuel mix ratio because the engine isn't yet warmed up. So mix control is handled by a program stored in computer memory

Closed loop means it is now adjusting the engine based off sensors.
It sounds kinda like your car has a problem running closed loop but you say this problem happens when the engine gets really hot
like after a half hour. I think the engine goes into closed loop after about 15 minutes. So maybe if the car is overheating, it could be some
kind of vapor lock. Have you got anyway to check how hot your engine is really getting?

If you take off the intake pipe to you air filter when the engine is hot. Then start the car, when it tries to die, spray a small amount
of starting fluid into the intake. If the engine runs better, you are too lean. If it makes no difference it maybe ignition related.

I don't know what wires are on there but I know there are some crappy ones out there. If yours are radio suppression carbon
track type, you need to check each with an ohm meter. They should read 10-20,000 ohms each. If you get one that reads way high,
you may have an internal arcing that burned the inside. I have had this issue with new after market wires on a non turbo car.
And it caused the car to stall while idling coming to a stop. Look inside the boot, do you see a bright shiny wire in the center bent
around to the metal clip the contacts the plug or is it dark grey looking? If it grey, then it is radio suppression.

Good luck

I try to do the paper clip trick to ground it out in the upper right pins on that thing under the ashtray and the ses light just keeps flashing. I have an 84 gn with a 86 ECM so thats why I believe its on. Thanks for the definitions, they make sence.... I will do a test on the plug wires today, should I test them when the engine is hot or cold or both? thanks

 

[mccallumfam1]

Well . . . .The 84/85 module is different and will not even work with a Caspers tester, unless you have the correct pigtail, that was the reason I asked “How”.
To the best of my knowledge, the 84-85 mudules pretty much stand on their own.
So, it doesn't matter if the shop/store has $1,000,000 piece of equipment just to test modules. It will indicate a “fail” every time, unless they have this information.

Re: Conversion.
Yes, that is all you need.

If I remember (CRS here . . LOL) the SES code was “12”, so that is good.
Now . . . If you drive the car, get an SES code, and then when you inspect it is code 12, the ECM is losing power and resetting.
If the grounds are correct, you will need to check other connections. (Battery, body grounds, starter connections, ECM connector at the battery, etc)

Also . . . Hard starting . . . can very possibly be the module, a bad wire, FP relay, etc.
I have chased a major intermittent problem for 9 years and finally found it. It showed up under the right circumstances and could not be seen on a scantool.
It is so stupid small I am not even going to post about it. I learned a heck of a lot in the process, BUT also gained a lot of grey hairs in the process! LOL



I have seen crank sensors act up as well, and that is why I say “Check for spark when she quits and will not restart”
Having stated all that . . . . the messages and my responses are more than likely very conflicting to you in many ways.

If it does not shut off like turning the ignition off, it is probably not the crank sensor.
If it does not start due to “heat soak”, a 10 minute cool down will not be significant for the module to “start and run fine”.

Stock idle is around 775-800 so it looks a lot closer than before.
Make sure the throttle is not sticking or transmission cable too tight.
You can disconnect the transmission cable at the T.B. (DO NOT DRIVE IT THIS WAY!) and see of the idle drops.

Best way to check for vacuum leaks . . . no such thing . . as some people check differently based on application and tools.
Smoke test is good one, but requires a pressure set-up and smoke machine.
Carb cleaner sprayed around the other areas is good, for bigger leaks.
Propane bottle works too, but on a HA it is almost impossible if you have the mechanical fan.
My method . . . Pinching the hoses one at a time and listening/monitoring RPM is the better method . . . once you find the hose, you can spray with some carb cleaner. . . . Oh, I verify the O2's on the scantool when I spray . . . LOL [/quote]

I believe you hit the nail on the head with this one, That makes all the sence that those modules are tested bad, They are not being tested correcttly according to what your saying. An additional pigtail is needed to test the hotair modules. Thats also why the 86-87 module I had tested passed. That makes sence. I will try to look for vacuum leaks again today. When I tried to pinch the vacuum lines, I went through them all and the idle would not change but I will try to do it now that I have the idle lower now. Also could wires be a culprit here. My problem only reveals itself when it gets nice and hot. That I do know forsure lol. thats about all I know. oh yeah where do I adjust the tranny cable on the Throttle body with my pedal to the floor? Right now at idle, there is about a half inch of cable on the other side before the throttle engages the tranny cable. The cable doesnt seem to be too tight,
thanks jerryl u tha man

 

[standupjskiguy]

It's not a paper clip to ground it is a paper clip across those two terminals shown.
The SES light flashes a number, example, flash,,,flash,flash,,,that is number 1-2, it will repeat, flash,,,flash,flash three times, then if there is another code it will flash that for example, flash,,,flash,flash,flash,flash,,,that would be a 1-4, it will flash that three times, do you understand? If no other codes are stored it will flash 1-2 again that is how you know there are no more codes.
The code 1-2 or twelve, just means your engine is not running, I.e. no distributor signal, a code 12 is normal.
BTW, I'm not sure on these turbo cars but on my van, the fan runs while I'm retrieving codes.
RE: Plugs wires? ,,, it doesn't matter but for comfort, I'd check them engine cool.

 

[mccallumfam1]

It's not a paper clip to ground it is a paper clip across those two terminals shown.
The SES light flashes a number, example, flash,,,flash,flash,,,that is number 1-2, it will repeat, flash,,,flash,flash three times, then if there is another code it will flash that for example, flash,,,flash,flash,flash,flash,,,that would be a 1-4, it will flash that three times, do you understand? If no other codes are stored it will flash 1-2 again that is how you know there are no more codes.
The code 1-2 or twelve, just means your engine is not running, I.e. no distributor signal, a code 12 is normal.
BTW, I'm not sure on these turbo cars but on my van, the fan runs while I'm retrieving codes.
RE: Plugs wires? ,,, it doesn't matter but for comfort, I'd check them engine cool.

I understand that, I ground out the two terminals in the upper right corner of plug under the ashtray, I tried it a couple times, and the SES light keeps flashing, and not the one long two short one long and two short that it should, It just keeps blinking continuisly , blink blink blink blink blink blink blink and so on? Why could this be? as for the fan it doesnt run while i try the test and I will make sure the engine is cool when testin the wires lol hahaha

 

[mccallumfam1]

Well . . . .The 84/85 module is different and will not even work with a Caspers tester, unless you have the correct pigtail, that was the reason I asked “How”.
To the best of my knowledge, the 84-85 mudules pretty much stand on their own.
So, it doesn't matter if the shop/store has $1,000,000 piece of equipment just to test modules. It will indicate a “fail” every time, unless they have this information.

Re: Conversion.
Yes, that is all you need.

If I remember (CRS here . . LOL) the SES code was “12”, so that is good.
Now . . . If you drive the car, get an SES code, and then when you inspect it is code 12, the ECM is losing power and resetting.
If the grounds are correct, you will need to check other connections. (Battery, body grounds, starter connections, ECM connector at the battery, etc)

Also . . . Hard starting . . . can very possibly be the module, a bad wire, FP relay, etc.
I have chased a major intermittent problem for 9 years and finally found it. It showed up under the right circumstances and could not be seen on a scantool.
It is so stupid small I am not even going to post about it. I learned a heck of a lot in the process, BUT also gained a lot of grey hairs in the process! LOL



I have seen crank sensors act up as well, and that is why I say “Check for spark when she quits and will not restart”
Having stated all that . . . . the messages and my responses are more than likely very conflicting to you in many ways.

If it does not shut off like turning the ignition off, it is probably not the crank sensor.
If it does not start due to “heat soak”, a 10 minute cool down will not be significant for the module to “start and run fine”.

Stock idle is around 775-800 so it looks a lot closer than before.
Make sure the throttle is not sticking or transmission cable too tight.
You can disconnect the transmission cable at the T.B. (DO NOT DRIVE IT THIS WAY!) and see of the idle drops.

Best way to check for vacuum leaks . . . no such thing . . as some people check differently based on application and tools.
Smoke test is good one, but requires a pressure set-up and smoke machine.
Carb cleaner sprayed around the other areas is good, for bigger leaks.
Propane bottle works too, but on a HA it is almost impossible if you have the mechanical fan.
My method . . . Pinching the hoses one at a time and listening/monitoring RPM is the better method . . . once you find the hose, you can spray with some carb cleaner. . . . Oh, I verify the O2's on the scantool when I spray . . . LOL [/quote]


Just to be clear I have a 84 HA GN with 84-85 coil and module, 84-85 MAF and 86 ECM, is this setup the reason causing my issues or is this acceptable? Or is this the root of my problem? I think the SES is on because of that ecm. I ground out the two terminals in the upper right corner of plug under the ashtray, I tried it a couple times, and the SES light keeps flashing, and not the one long two short one long and two short that it should, It just keeps blinking continuisly , blink blink blink blink blink blink blink and so on? Why could this be?

 

[standupjskiguy]

I know code numbers can go high but if your saying you get nothing but a continuous blinking light that doesn't pause,
I have no answer for you. I hope someone else knows. Maybe an internet search for that phrase might help.
Slightly off your topic, if you have no use for the 84-85 ignition module and coil pack.
I want to buy a spare for my 85 if you'd be interested in selling it.

 

[Jerryl]

Just to be clear I have a 84 HA GN with 84-85 coil and module, 84-85 MAF and 86 ECM, is this setup the reason causing my issues or is this acceptable? Or is this the root of my problem? I think the SES is on because of that ecm. I ground out the two terminals in the upper right corner of plug under the ashtray, I tried it a couple times, and the SES light keeps flashing, and not the one long two short one long and two short that it should, It just keeps blinking continuisly , blink blink blink blink blink blink blink and so on? Why could this be?

Yes, you have the code with the new ECM because you are missing the IAT sensor. That should be a code 23. If you look at the link, you will also see how to add one. Real easy. Are you running a custom chip for YOUR set-up in the 86 ECM? http://www.vortexbuicks-etc.com/trouble_codes.htm
Flasing is not short/long, just once and than twice. At tihis time I suggest you put the HA ECM back on the car to eliminate variables and the IAT code . . . and see if another one shows up.
You can run 86 ECM with HA Ignition and MAF. The only questionable item is the MAF. Some had good luck, other did not. This purely performance related and it should not affect starting if the MAF is in good condition. The easiest way to tell how good the MAF is on the set-up is with a recording scantool.

 

[mccallumfam1]

Yes, you have the code with the new ECM because you are missing the IAT sensor. That should be a code 23. If you look at the link, you will also see how to add one. Real easy. Are you running a custom chip for YOUR set-up in the 86 ECM? http://www.vortexbuicks-etc.com/trouble_codes.htm
Flasing is not short/long, just once and than twice. At tihis time I suggest you put the HA ECM back on the car to eliminate variables and the IAT code . . . and see if another one shows up.
You can run 86 ECM with HA Ignition and MAF. The only questionable item is the MAF. Some had good luck, other did not. This purely performance related and it should not affect starting if the MAF is in good condition. The easiest way to tell how good the MAF is on the set-up is with a recording scantool.

Thanks I will try an original hot air ecm and the go from there. What cars from the junkyard would use the same ecm as a hotair ???? I got the car with a 86 ecm in it.... also would you think I could have fuel pump problems? This car has a new tank, pump, lines and filter.. but ya never know? where is the fuel pressure relay located? is it along the fender on the passenger side??? The car did the same thing again today, ran good til warm and then stumbled and died. I will buy a fuel pressure gauge and I will let u know what happens. I checked the ground under the ac comp and it looks tight and clean, also alternator and starter grounds aswell. This car is being a pain......

 

[Jerryl]

Thanks I will try an original hot air ecm and the go from there. What cars from the junkyard would use the same ecm as a hotair ???? I got the car with a 86 ecm in it.... also would you think I could have fuel pump problems? This car has a new tank, pump, lines and filter.. but ya never know? where is the fuel pressure relay located? is it along the fender on the passenger side??? The car did the same thing again today, ran good til warm and then stumbled and died. I will buy a fuel pressure gauge and I will let u know what happens. I checked the ground under the ac comp and it looks tight and clean, also alternator and starter grounds aswell. This car is being a pain......

If you have the 86 ECM already, just order a chip from TurboTweak, and tell him the IAT sensor is not installed. (Check to make sure)
You can also order the scanmaster at the same time.
Either way, be sure you have a chip for YOUR set-up, not some other chip someone told you would work.
For some reasons, I thought you swapped the ECM to diagnose the problem.

The FP relay is on the PS side. New pump is good but you need to verify the pressure as it may be bad.
Did the car ever run correctly with the current set-up?

 

[DMAC]

Here is a Grand National Donor Part Listing

 

[mccallumfam1]

If you have the 86 ECM already, just order a chip from TurboTweak, and tell him the IAT sensor is not installed. (Check to make sure)
You can also order the scanmaster at the same time.
Either way, be sure you have a chip for YOUR set-up, not some other chip someone told you would work.
For some reasons, I thought you swapped the ECM to diagnose the problem.

The FP relay is on the PS side. New pump is good but you need to verify the pressure as it may be bad.
Did the car ever run correctly with the current set-up?

According to the P.O it did, I drove it around town last summer when the P.O owned it and it ran great around town. I know the previous owner real good. He said he took the car on a trip out of the province, Then this spring I drove about 2hrs out of town to buy it, I put a new battery in it and it fired up right away. swapped the oil out right away, and pumped a full tank of premium in it, I beleive the P.O was using regular. On the highway it ran good and the same thing happened, let off the gas or slowed down to make a corner and the dam thing would die out. pop the hood wait another 5 min and go until the next time I let off the gas or come to a stop sign.?????????????? I will try find an 84-84 ecm before I order the tt chip wit the IAT sensor not installed.

 

[mccallumfam1]

Here is a Grand National Donor Part Listing

I already have a 86 ecm and was wondering if I could find a compatible 84-85 ecm from the boneyard

 

[standupjskiguy]

I doubt you will find one at a boneyard, the car is too rare.
Look in parts for sale section here, I believe I saw this guy, "selling 23 years of parts", I believe he has an 84-85 ECM for $40.

 

[mccallumfam1]

I know code numbers can go high but if your saying you get nothing but a continuous blinking light that doesn't pause,
I have no answer for you. I hope someone else knows. Maybe an internet search for that phrase might help.
Slightly off your topic, if you have no use for the 84-85 ignition module and coil pack.
I want to buy a spare for my 85 if you'd be interested in selling it.

Sure I got two sets of them, I will probrebly do a conversion soon, You can take it for $50 Plus shipping, I live in canada. Send me your full address if u want it.

 

[mccallumfam1]

If you have the 86 ECM already, just order a chip from TurboTweak, and tell him the IAT sensor is not installed. (Check to make sure)
You can also order the scanmaster at the same time.
Either way, be sure you have a chip for YOUR set-up, not some other chip someone told you would work.
For some reasons, I thought you swapped the ECM to diagnose the problem.

The FP relay is on the PS side. New pump is good but you need to verify the pressure as it may be bad.
Did the car ever run correctly with the current set-up?

Also do TPS sensors and IAC motors go bad in this situation?